1. Field of the Invention
The present invention relates to a sheet feeding device for cutting an elongate sheet paid out from a roll at a preselected length and conveying the cut sheet and an image forming apparatus using the same.
2. Description of the Background Art
Generally, an image forming apparatus of the type using an elongate sheet implemented as a roll uses either one of a guillotine type cutter and a rotary type cutter for cutting the sheet. Japanese Patent Laid-Open Publication Nos. 11-48553 and 6-278938, for example, each discloses a cutter in the form of a rotary edge movable back and forth in the widthwise direction of a sheet.
An image forming apparatus of the type using a rotary edge mentioned above may be configured to allow the operator of the apparatus to move the cutter by hand for the replacement or the replenishment of a sheet after opening the cover of a sheet storing section and turning off a power switch, as proposed in the past. By moving the cutter in the widthwise direction of a sheet by hand, the operator can cut the leading edge of a new sheet replaced or replenished at a preselected position. In this type of image forming apparatus, after the operator has cut the leading edge of the new sheet, closed the cover of a sheet storing section and then turned on a power switch, the cutter is automatically returned to a reference position outside of a sheet conveyance range by power. This is because the operator may have left the cutter within the sheet conveyance range.
To return the cutter to the reference position, two cutter sensors are positioned at opposite reference positions outside of the sheet conveyance range. Whether or not the cutter has been returned to the reference position is determined on the basis of the output signals of the two cutter sensors. If the answer of this decision is negative, then control is executed to return the cutter to the reference position outside of the sheet conveyance range.
The conventional image forming apparatus of the type described has the following problem left unsolved. Assume that the operator cut the leading edge of a new sheet by moving the cutter by hand leaves the cutter at a position within the sheet conveyance range. Then, after the operator has closed the cover of the sheet storing section and then turned on the power switch, the cutter is automatically moved to the reference position and therefore again cuts the leading edge of the sheet already cut by the manual operation. The cutter can accurately cut a sheet when the portion of the sheet to be cut is remote from the leading edge by a preselected dimension. However, when the cutter is automatically moved along the edge of the sheet already cut by manual operation, the edge of the sheet moves relative to the cutter and is therefore folded or bent due to interference with the cutter or is only partly cut in the widthwise direction. As a result, the leading edge of the sheet cut by the cutter is defective.
Technologies relating to the present invention are also disclosed in, e.g., Japanese Patent Laid-Open Publication Nos. 8-12148 and 10-129900.
It is an object of the present invention to provide a sheet feeding device capable of preventing, even when a cutter is left in a sheet conveyance range after the replacement or the replenishment of a roll, the cutter from again cutting the leading edge of a sheet when returning to a reference position for thereby obviating defective cuffing, and an image forming apparatus using the same.
A sheet feeding device of the present invention includes a sheet storing section configured to store an elongate sheet implemented as a roll. The sheet paid out from the sheet storing section is conveyed to a preselected position via an outlet. Feed members are driven by a reversible feed motor for feeding the sheet via the outlet. A cutter is capable of being moved back and forth by hand between two reference positions located outside of and opposite sides of the widthwise range of the sheet. A drive section causes the cutter to move back and forth with power. A position recognizing device recognizes a position where the cutter is held in a halt. When the position recognizing device determines that the cutter is held in a halt at a position other than the reference positions, a reverse conveying device causes the feed members to return the leading edge of the sheet toward the upstream side in the direction sheet feed over the cutter by a preselected amount. Further, when the position recognizing device determines that the cutter is held in a halt at a position other than the reference positions, a returning device causes the drive section to return the cutter to either one of the reference positions after the reverse conveying device has returned the sheet.